[bb99slt]

HI,
Im new to the board but need help. My D shifts fine from 1 - 2 but dosent seem to know when to shift form 2 - 3. About 1 in 10 times it is fine and the other times it revs way up before shifing. Once in 3rd it goes between 3 - 4 no problem. It does seem to be getting worse. Can anyone help! It is a 99 with a 5.9. I have tried blipping the throttle and even just letting off and it still dosent want to shift. I have also tried shifting it manually with no real improvment? It dosent feel like it is slipping when it shifts. It seem that it just isnt even trying.
Have you gotten your problem solved?
John

had EXACTLY the same symptoms ... the fix was a tranny re-build.. to replace the seals. for a mere $1500

In particular the seal on the "direct drum" leaks when it gets old (at around 60 K) because the groove on the direct drum was cut too deep .. right from the D-C factory

good luck on the re-build .. and make sure they use ATF+4 to fill the tranny

 

[bb99slt]

hope your fix did the trick!
my tranny was diagnosed by 3 different tranny shops and they said all the pressures were normal, so replacing the stuff you did would not help (in my case)

wish i coulda gotten away with only $200